In recent years, MEMS structures produced using a MEMS technique have been used for various sensors (for example, an acceleration sensor, a gyro sensor, and the like) for detecting physical quantities. Each of the MEMS structures used for such sensors has a movable portion that can be displaced according to an external cause, and is configured to detect a physical quantity by converting deformation and displacement of the movable portion into an electrical signal and outputting the electrical signal.
As an invention regarding such a MEMS structure, the invention described in Japanese Patent Laying-Open No. 2008-058259 (Patent Document 1) has been known, for example. Patent Document 1 describes an inertia sensor capable of detecting, by way of driving oscillation in a direction of first axis of three axes orthogonal to one another, an angular velocity in a direction of second axis. In the inertia sensor described in Patent Document 1, an oscillator, which serves as the movable portion, is supported by an elastic supporting portion to be displaceable in a predetermined driving direction (for example, X-axis direction) and a detection direction (for example, Y-axis direction/Z-axis direction) orthogonal to the driving direction. The inertia sensor is configured such that displacement of the movable portion in the detection direction can be detected by a detection electrode as a change of capacitance. Therefore, in Patent Document 1, the elastic supporting portion for supporting the movable portion is configured to be elastically deformable, and has degrees of freedom in the driving direction and the two detection directions.